The guilty verdict delivered against former Osama bin Laden driver Salim Ahmed Hamdan on Wednesday establishes a legal precedent that will make it easier for prosecutors to convict other suspected war criminals in military commission trials at Guantánamo Bay, Cuba.

Mr. Hamdan, a Yemeni national, was convicted of providing material support to a terror group. But the six-member war crimes tribunal also found Hamdan not guilty of charges that he was a willing participant with Al Qaeda in a terror conspiracy.

The split verdict comes in the first war crimes tribunal conducted by the US military since World War II. The military commission, made up of six officers hand-picked by the Pentagon, reached its verdict after eight hours of deliberations over three days.

Deputy White House spokesman Tony Fratto said the administration was "pleased" with the outcome. "We look forward to other cases moving forward to trial," he said.

The Bush administration has faced a heated debate and a barrage of legal challenges over its plan to use the Guantánamo terror prison camp as a venue for bringing Al Qaeda suspects to justice.

Supporters of the commission system say its stripped-down trial protections are necessary to safeguard sensitive intelligence sources and methods while providing a fair trial. Critics say the process is rigged to produce convictions and cover up alleged torture and other mistreatment of terror suspects.

"Any verdict resulting from such a flawed system is a betrayal of American values," says Anthony Romero, executive director of the American Civil Liberties Union. "The rules for the Guantánamo military commissions are so flawed that justice could never be served. From start to finish, this has been a monumental debacle of American justice."

Americans might expect that Hamdan, now a convicted war criminal, personally engaged in the ruthless tactics of a terrorist or a mass murderer. But no evidence was presented during the 10-day trial that Hamdan ever personally killed, injured, or harmed anyone.

His participation in Al Qaeda's mass murder was indirect, according to the evidence heard by the military commission. He served as Mr. bin Laden's driver and bodyguard, transported weapons to Al Qaeda members, and received weapons training, according to testimony.

Hamdan's lawyers say these activities are not war crimes and should not be prosecuted as war crimes.

Defense lawyers said Hamdan was a mere employee, a $200-a-month driver for the Al Qaeda leader, not a committed jihadist involved in plotting and carrying out terror attacks.

Prosecutors countered that Hamdan was a trusted member of Bin Laden's inner circle. A criminal investigator with the Navy testified that Hamdan admitted under questioning that he'd sworn a loyalty oath to Bin Laden. When Hamdan was captured, soldiers found two SA-7 surface-to-air missiles in his car.

Defense lawyers presented the written testimony of alleged 9/11 mastermind Khaled Shaikh Mohammed, who is facing his own trial at Guantánamo. He told the commission that Hamdan was a civilian employee, not a holy warrior.

"He was a driver and auto mechanic … he was not at all a military man," Mr. Mohammed wrote.

Hamdan's conviction is important to the US government because it establishes a legal foundation within the controversial military commission system for future trials. It sets a relatively low bar for prosecutors, even if they have skimpy evidence.

It suggests that in future cases in which some evidence has been withheld to avoid disclosure of harsh interrogation methods or barred from trial because the information is deemed unreliable, military prosecutors might still obtain convictions on the theory that any involvement with Al Qaeda helped the group commit future terror attacks.

Hamdan is entitled to appeal his conviction in both military and civilian appeals courts. The appeal is expected to feature a comprehensive legal challenge to the military commission process. It is an appeal that could take the case to the US Supreme Court.

Legal analysts expect Hamdan's lawyers to challenge the government's use of material support as a war crime. In pretrial motions, they argued that Hamdan's alleged involvement with Al Qaeda is said to have occurred between 1996 and November 2001. But the Military Commissions Act designating material support as a war crime was not enacted until 2006. They argued that it amounts to an unconstitutional ex post facto law.

Even if he'd been acquitted of all charges, Hamdan was unlikely to be released from his Guantánamo cell anytime soon. In addition to the military commission charges, Hamdan is being held in open-ended detention as an unlawful enemy combatant.

Under the law of war, he can be held for the duration of the war on terror.

"Hamdan suffered nearly seven years of unlawful detention, only to face a process that falls far short," Mr. Cox said. The administration, he added, is continuing to try to "escape the rule of law and the requirements of justice" by relying on the commission process at Guantánamo.

"This system was devised to permit the prosecution of alleged wrongdoing by detainees, while continuing to cover up the wrongdoing by government interrogators," adds Mr. Romero of the ACLU. "Trials that are shrouded in secrecy and tainted by coercion are the very antithesis of American justice."